The use of plasmas in the analysis of samples is well known. Generally, a sample in a nebulized form, is entered to a space inside a tube in which a plasma is caused to exist, and resulting emitted electromagnetic radiation is directed into a system for identifying the wavelength(s) present therein. Said present wavelength(s) are identifying of certain molecular and elemental contents of said sample.
A problem which can present during use of plasma based sample analysis systems is that some samples, even in highly nebulized form, (e.g. particles of thirteen (13) microns or less in diameter), can be difficult for plasmas to dissociate into component molecules and/or elemental atoms. This is often true, for instance, when sample is present in a molecular oxide form. Use of a higher energy plasma is, of course, one approach to overcoming the problem and can provide valuable results, particularly when it is desired to completely fragment the sample into elemental components. Another approach to the problem would be to expose nebulized sample to dissociated volatile atoms prior to entry thereof into a plasma, so that volatile, more easily dissociated, sample component containing molecules of are formed, (such as hydrides and/or fluorides), and injected into said plasma instead of originally present, more stable, sample component containing molecules.
A search for Patents which describe the use of volatile atoms to create volatile compounds with sample components prior to the entering thereof into a plasma indicates that little has been done in the area.
A Patent to Sauers, U.S. Pat. No. 4,633,082 is perhaps the most relevant reference discovered, but it describes a system for detecting breakdown of electrical equipment. This Patent states that sulfur-hexafluoride gas is often utilized as an insulator in high voltage systems. Electrical breakdown occurring in said high voltage systems causes formation fluorides of contaminants inside said high voltage equipments, which fluorides can be detected by, for instance, gas chromatography systems. Periodic sampling and analysis of the sulfur-hexafluoride insulating gas can thus provide early detection of electrical breakdown inside said electrical equipment.
Another Patent, U.S. Pat. No. 4,378,499 to Spanger et al. describes a system for detecting ion mobility. Selectivity and sensitivity are enhanced by converting through surface interactions sample gas or vapor to a form more readily ionized or by converting through surface interactions interferent gas or vapor to a form less readily ionized. Use of fluoride salts are mentioned as suitable for halogenating organophospherous compounds.
U.S. Pat. No. 5,089,746 to Rosenblum describes the use of fluorine in a feed gas dissociated in a plasma to react with a boron containing liner to form volatile species which more easily leave the surface thereof. The purpose is to facilitate provision of boron in a beam for use ion implantation.
A Patent to Strusand et al., describes the presence of a mixing chamber into which a sample of reactive gas or vapor is caused to flow, wherein it is mixed with a plasma gas including water vapor or solvent.
No known reference, however, teaches that a sample in a nebulized form should be caused to mix with volatile dissociated fluorine and/or hydrogen atoms, for instance, prior to entry into a plasma based sample analysis system plasma, to provide enhancement of the limit of detection of nebulized sample components. A need exists for such a system and method of use.